The vertebrae of an individual's spine should be in neutral alignment while sleeping, in order to increase the individuals comfort, and reduce neck and back strain. If the neck support in a pillow is too high or too low, the vertebrae in the neck will be out of alignment with the vertebrae in the rest of the spine. This may reduce the restfulness of the individual's sleep, and aggravate neck and back problems. The level of neck support required will vary according to body size and sleeping position. Accordingly, it is desirable to have an adjustable neck support which can be quickly and easily adjusted by the individual, while lying down. It is also desirable for the pillow to distribute the body weight of the individual to decrease compression on compression points. These features will increase comfort levels, and reduce neck and back strain.
The development of visco-elastic foam has introduced a technology that revolutionizes sleeping systems. Visco-elastic foam may be preformed into an orthopaedically designed contour pillow, which provides improved support for a user's head and neck. Visco-elastic foam provides comfort and health benefits because it is heat and pressure sensitive and thereby responds to body weight and temperature by molding to the individual. This provides more evenly distributed support and decreases compression on compression points. However, this technology suffers from at least two limitations. First, because the ideal level of neck support varies depending on the user's body size and sleeping position, a pre-formed visco-elastic pillow will not provide adequate neck support for all users in all sleeping positions. Secondly, because the visco-elastic foam molds to the individual, the support in the neck region may not be sufficiently firm. Accordingly, there is a need for a preformed visco-elastic pillow with a neck support which can be custom-adjusted to suit the user's individual needs and sleeping patterns.
There have been numerous attempts to develop adjustable pillows. However, all of the previous products have suffered from one or more shortcomings. Japanese Patent 81.34 116 to M. Genda discloses an L-shaped pillow overlying an air bag. The height of the entire pillow can be raised or lowered by injecting or discharging air from the air bag; however, it is not possible to adjust the level of neck support relative to the rest of the pillow. Accordingly, one cannot custom adjust the level of neck support to ensure that the vertebrae are in neutral alignment. Furthermore, given the large size of the air pillow, it would be relatively difficult to effect rapid changes in the height of the pillow. U.S. Pat. No. 4,829,614 to J. Harper discloses an adjustable pillow with at least three air chambers for adjusting support to the head, neck, and shoulders. However, this device is relatively cumbersome to inflate and deflate to desired levels because the invention lacks a hand-operated air pump or other device which would permit the user to quickly adjust the air levels when changing their sleeping position. Furthermore, the use of multiple air chambers would lead to an uneven and uncomfortable surface beneath the head. Moreover, the adjustable pillows disclosed in the prior art utilizing an air bag do not provide the health benefits and comfort of visco-elastic foam.